Preparation and characterization of temperature sensitive iron oxide nanoparticle and its application on enhanced oil recovery

To increase oil production, temperature sensitive iron oxide nanoparticles (TSIO) were prepared and used in enhanced oil recovery process. Iron oxide (IO) was synthesized by hydrothermal method, and then modified in situ with poly (N-isopropylacrylamide) (PNIPAM) and styrene sulfonate groups. The morphology and the structure of the TSIO nanoparticles were characterized by FTIR and TEM. The contact angle and the interfacial tension were carried out. The results showed that TSIO not only changed the wettability of the rocks, but also reduced the interfacial tension of the oil and water, which was conducive to improving the efficiency of oil recovery. When the temperature was higher than the critical temperature, the size of the nanoparticles gradually decreased, which greatly reduced the wettability of the rocks and the interfacial tension of the oil and water. Interestingly, TSIO was not only stably dispersed in water, but was also present in salt water. Microscopic displacement experiments had confirmed that the effect of TSIO-based nanofluid on oil recovery at room temperature increased from 65.78% to 74.15%. When the temperature raised to 50 °C, the recovery rate raised to 84.02%. The results indicated that TSIO-based nanofluids had the potential to enhance oil recovery.